IJMMS 1986 Volume 24 Issue 1

The human-computer interface is increasingly the major determinant of the
success or failure of computer systems. It is time that we provided
foundations of engineering human-computer interaction (HCI) as explicit and
well-founded as those for hardware and software engineering. Computing
technology has progressed though a repeated pattern of breakthroughs in one
technology, leading to its playing a key role in initiating a new generation.
The basic technologies of electronics, virtual machines, and software have gone
through cycles of breakthrough, replication, empiricism, theory, automation and
maturity. HCI entered its period of theoretical consolidation at the beginning
of the fifth generation in 1980. The lists of pragmatic dialog rules for HCI
in the fourth generation have served their purpose, and effort should now be
directed to the underlying foundations. The recently announced
sixth-generation computer system (SGCS) development program is targeted on
these foundations and the formulation of knowledge science. This paper surveys
the development of HCI and related topics in artificial intelligence; their
history, foundations, and relations to other computing disciplines. The
companion paper surveys topics relating to future developments in HCI.

An Experimental Comparison of a Mouse and Arrow-Jump Keys for an Interactive
Encyclopedia

This paper reports on an experiment which was conducted to examine relative
merits of using a mouse or arrow-jump keys to select text in an interactive
encyclopedia. Timed path traversals were performed by subjects using each
device, and were followed by subjective questions. Personality and background
of the subjects were recorded to see if those attributes would affect device
preference and performance. The arrow-jump keys were found to have the
quickest traversal times for paths with either short or long target distances.
The subjective responses indicated that the arrow-jump method was
overwhelmingly preferred over the mouse method. Personality type was not found
to play a critical role.

The User's Mental Model of an Information Retrieval System: An Experiment on
a Prototype Online Catalog

An empirical study was performed to train naive subjects in the use of a
prototype Boolean logic-based information retrieval system on a database of
bibliographic records. The research was based on the mental models theory
which proposes that people can be trained to develop a "mental model" or a
qualitative simulation of a system which will aid in generating methods for
interacting with the system, debugging errors, and keeping track of one's place
in the system. It follows that conceptual training based on a system model
will be superior to procedural training based on the mechanics of the system.
We performed a laboratory experiment with two training conditions (model and
procedural), and with each condition split by sex. Forty-three subjects
participated in the experiment, but only 32 were able to reach the minimum
competency level required to complete the experiment. The data analysis
incorporated time-stamped monitoring data, personal characteristics variables,
affective variables, and interview data in which subjects described how they
thought the system worked (an articulation of the model). As predicted, the
model-based training had no effect on the ability to perform simple, procedural
tasks, but subjects trained with a model performed better on complex tasks that
required extrapolation from the basic operations of the system. A stochastic
process analysis of search-state transitions reinforced this conclusion.
Subjects had difficulty articulating a model of the system, and we found no
differences in articulation by condition. The high number of subjects (26%)
who were unable to pass the benchmark test indicates that the retrieval tasks
were inherently difficult. More interestingly, those who dropped out were
significantly more likely to be humanities or social science majors than
science or engineering majors, suggesting important individual differences and
equity issues. The sex-related differences were slight, although significant,
and suggest future research questions.

Fuzzy cognitive maps (FCMs) are fuzzy-graph structures for representing
causal reasoning. Their fuzziness allows hazy degrees of causality between
hazy causal objects (concepts). Their graph structure allows systematic causal
propagation, in particular forward and backward chaining, and it allows
knowledge bases to be grown by connecting different FCMs. FCMs are especially
applicable to soft knowledge domains and several example FCMs are given.
Causality is represented as a fuzzy relation on causal concepts. A fuzzy
causal algebra for governing causal propagation on FCMs is developed. FCM
matrix representation and matrix operations are presented in the Appendix.

This paper proposes an architecture for building better Computer-Assisted
Instruction (CAI) programs by applying and extending Artificial Intelligence
(AI) techniques which were developed for planning and controlling the actions
of robots. A detailed example shows how programs built according to this
architecture are able to plan global teaching strategies using local
information. Since the student's behavior can never be accurately predicted,
the pre-planned teaching strategies may be foiled by sudden surprises and
obstacles. In such cases, the planning component of the program is dynamically
reinvoked to revise the unsuccessful strategy, often by recognizing student
misconceptions and planning a means to correct them. This plan-based teaching
strategy scheme makes use of global course knowledge in a flexible way that
avoids the rigidity of earlier CAI systems. It also allows larger courses to
be built than has been possible in most AI-based "intelligent tutoring systems"
(ITSs), which seldom address the problem of global teaching strategies.

IJMMS 1986 Volume 24 Issue 2

Foundations of Dialog Engineering: The Development of Human-Computer
Interaction. Part II

The human-computer interface is increasingly the major determinant of the
success or failure of computer systems. It is time that we provided
foundations of engineering human-computer interaction (HCI) as explicit and
well-founded as those for hardware and software engineering. Through the
influences of other disciplines and their contribution to software engineering,
a rich environment for HCI studies, theory and applications now exists. Many
principles underlying HCI have systemic foundations independent of the nature
of the systems taking part and these may be analysed control-theoretically and
information-theoretically. The fundamental principles at different levels may
be used in the practical design of dialog shells for engineering effective HCI.
This paper surveys the development of styles of dialog through generations of
computers, the principles involved, and the move towards integrated systems.
It then systematically explores the foundations of HCI by analysing the various
analogies to HCI possible when the parties are taken to be general systems,
equipment, computers or people.

Comparison of Decision Support Strategies in Expert Consultation Systems

Different strategies of decision support can be identified in a consultation
process and implemented in an expert system. This paper concentrates on
experiments that were carried out with an expert system that was developed in
the area of information retrieval, to perform the job of an information
specialist who assists users in selecting query terms for database searches.
Three different support strategies are utilized in the system. One is a
"participative" strategy, in which the system performs a search within its
knowledge base and during which there is interaction between the system and the
user, whereby the system informs the user of intermediate findings and the user
judges their relevancy and directs the search. The second is a more
"independent" support strategy, in which the system performs a search and
evaluates its findings without informing the user before the search is
completed. The third is a "conventional" strategy (not an expert system) in
which the system only provides information according to the user's request, but
it does not make judgments/decisions; the user himself is expected to evaluate
and to decide.
Three main questions are examined in the experiments: (a) which of the three
support strategies or systems is more effective in suggesting the appropriate
query terms; (b) which of the approaches is preferred by users; and (c) which
of the expert systems is more efficient, i.e. more "accurate" and "fast" in
performing its consultation job. The experiments reveal that the performance
of the system with the first two strategies is similar, and it is significantly
better than the performance with the third strategy. Similarly, users
generally prefer these two strategies over the "conventional" strategy.
Between the first two, the more "independent" system behaves more
"intelligently" than the more "participative" one.

On the Suitability of Fuzzy Models: An Evaluation Through Fuzzy Integrals

The paper deals with a problem of evaluating the properties of a system on
the basis of the corresponding fuzzy model, its properties, and its quality
measured by a performance index. It is shown that a grade of satisfaction for
a property of the system may be calculated by means of a fuzzy integral with
respect to a fuzzy measure, where the latter corresponds to a quantitative
representation of the quality of the model constructed. Two properties of wide
significance in system analysis, controllability and predictability are studied
in detail.

ADDS -- A Dialogue Development System for the Ada Programming Language

A dialogue development system for the Ada programming language is described.
The system supports the production of multi-level adaptable interfaces and
provides the following features: input validation, user recovery/backtracking,
in-depth help facilities, user-performance monitoring and a variety of user
interface specification languages. In addition, development tools are provided
that enable dialogue specific software to be automatically generated from the
constituent specifications. Considerations are given to the use of multi-level
interfaces and the employment of such systems in studying user adaptability and
learning. The architecture of ADDS is described and some simple examples of
its use are given. Although ADDS is designed for, and implemented in, Ada, it
is structured in a manner that will make the features it supports more widely
applicable.

Training by Exploration: Facilitating the Transfer of Procedural Knowledge
Through Analogical Reasoning

This study compared exploration-based training and instruction-based
training as methods of acquiring and transferring procedural device knowledge,
and examined whether any differences in learning outcomes could be explained by
the trainees' use of analogical reasoning from either abstract or concrete
representations of devices in memory. The exploration trainees experimented
with three analogous simulated devices in order to discover the procedures
governing their operations, whereas the instructed trainees followed procedural
examples contained in manuals. After a 2-day post-training delay, trainees
were exposed to a novel transfer device, which was either analogous or
disanalogous to the three training devices. Performance on the novel device,
subjects' perceptions of the similarity among devices' functions and subjects'
recall (written and behavioral) of the three training devices' operations, all
provided data indicating that exploration-based training promoted the use of
analogical reasoning in knowledge transfer and facilitated the induction of
abstract device representations (schemas). No such claim could be made for
instruction-based training. Implications for the future of exploration as a
training method and suggestions for future research are discussed.

IJMMS 1986 Volume 24 Issue 3

This paper presents a taxonomy of user-oriented data functions. The
taxonomy is composed of a hierarchy of user-oriented functions plus command
names suggested by a group of potential users for those functions, classified
as generally required in data-processing systems. The taxonomy can be used for
commercial system design and evaluation and as a basis for further research.

A new star-hub structure of binary relations is discussed in the context of
the methodology of Q-analysis, and parallels are drawn with maximal rectangles
and Galois lattice structures. Although these structures generalize those of
Q-analysis, there remain problems due to the very large number of star-hub
pairs generated by fairly modest data sets. It is argued that more theory is
necessary, and some possibilities are discussed. It is suggested that the
criteria for defining new structures will come most fruitfully from the study
of the relationship between backcloth and the ways it constrains traffic.
Finally, it is argued that these combinatorial structures are still not
sufficient to fully describe complex systems and that for this one needs to
consider polyhedra in the context of N-ary relations.

A model of computer-human interaction is presented, viewing the interaction
as a hierarchy of virtual protocol dialogues. Each virtual protocol realizes
the dialogue on the level above itself and is in turn supported by a
lower-level protocol. This model is inspired by the OSI-model for computer
networks from the International Standards Organization. The virtual dialogue
approach enables the separation of technical features of new devices (e.g. a
mouse or a graphical display) from the conceptual features (e.g. menus or
windows). Also, it is possible to analyse error messages and other feedback as
part of the different protocols.

IJMMS 1986 Volume 24 Issue 4

Mode Errors: A User-Centered Analysis and Some Preventative Measures Using
Keying-Contingent Sound

It is often claimed that user interfaces of advanced integrated systems are
mode-free. However, if one applies the user-centered analysis developed in
this paper, it is clear that almost any system of realistic complexity will
have modes of some kind. By using this analysis it is also possible to
identify the situation in which modes are likely to give rise to errors and
those where they will not. Various measures for preventing mode errors are
suggested. One of these is to signal mode by generating sounds which are
contingent on the users' action. Experimental work presented shows that this
mode-dependent keying-contingent sound can be an effective way of making users
aware of mode changes. Mode errors were reduced to a third of the number
observed with a control group.

A Review and Synthesis of Recent Research in Intelligent Computer-Assisted
Instruction

Educational devices incorporating artificial intelligent (AI) would
"understand" what, whom and how they were teaching and could therefore tailor
content and method to the needs of an individual learner without being limited
to a repertoire of prespecified responses (as are conventional computer
assisted instruction systems). This article summarizes and synthesizes some of
the most important research in the development of stand-alone intelligent
computer-assisted instruction (ICAI) systems; a review of passive AI-based
educational tools (e.g. microworlds, "idea processors", empowering
environments) would require a separate discussion. ICAI tutors and coaches
have four major components: a knowledge base, a student model, a pedagogical
module and a user interface. Major current themes of research in the knowledge
base include studies of expert cognition, the transfer of meaning, and the
sequencing of content. Student-modelling issues focus on alternative ways to
represent a pupil's knowledge, errors and learning. Pedagogical strategies
used by ICAI devices range over presenting increasingly complex concepts or
problems, simulating phenomena, Socratic tutoring with correction of pupil
misconceptions and modelling of expert problem solving via coaching; the
central theme of research is finding overarching paradigms for explanation.
Language comprehension and generation topics which have special relevance to
intelligent tutors and coaches are also briefly reviewed. Overall, increasing
availability, decreasing cost and growing commercial interest in AI-based
educational devices are enhancing the development of ICAI systems. Limits on
the sophistication of user interfaces, on the scope of subject domains and on
current understanding of individual learning are all constraining the
effectiveness of computer tutors and coaches. The explicitness required for
constructing intelligent devices makes their evolution more difficult and time
consuming, but enriches the theoretical perspective which emerges. In brief,
the computational and economic enabling of ICAI is proceeding more rapidly than
are its empirical and cognitive foundations, but significant overall progress
is being made.

An Empirical Comparison of Model-Based and Explicit Communication for
Dynamic Human-Computer Task Allocation

When both a human and a computer in a system are capable of performing the
same tasks, task responsibilities may be allocated between them dynamically.
This study compared two methods of human-computer communication for dynamic
task allocation: explicit and model-based communication. With explicit
communication the human directed the computer and the computer did not perform
any actions on its own. With model-based communication the computer employed a
model of the human which predicted the human's actions and the computer used
this model to work on its own. Subjects performed a process monitoring task
using both of these allocation methods. In addition, in half the trials
subjects had knowledge of the computer's actions and in the other half they did
not. The results indicated that overall system performance was always better
under model-based communication, although human performance alone was better
with explicit communication. In addition, overall system and human performance
were higher when the human had knowledge of the computer's actions.

An Experimental Evaluation of Prefix and Postfix Notation in Command
Language Syntax

Commands in a command language usually consist of a verb plus object(s). A
designer must decide the word order in which elements will appear in the
command string. Many existing command languages use the format, verb-object,
often referred to as prefix notation. However, another feasible syntax is
object-verb, referred to as postfix notation. The objective of this study was
to determine whether one of these notations facilitates user performance. Two
command languages for a text editor were designed. One is based on the natural
word order of English, verb-object. The other is based on the reverse word
order, object-verb. Sixty subjects, all native speakers of English, were
blocked into three groups: novices, experienced subjects who normally used a
line editor, and experienced subjects who normally used a screen editor.
Subjects were randomly assigned to use one of the command languages. They
learned to use the command language by self instruction, then were given 20 min
to perform a manuscript editing task. The task was deliberately made too long
for any subject to finish. Measures of performance used were: percentage of
task completed, percentage of erroneous commands, and editing efficiency. A
two-way ANOVA was performed on each of the three dependent variables. There
were no significant differences in performance between subjects who used the
prefix command language and those who used the postfix command language,
contrary to intuitive expectations. The novices differed significantly from
the experienced subjects on percentage of task completed and percentage of
erroneous commands, as expected. However, there was no significant difference
between the novices and experienced subjects on the measure of editing
efficiency. Variables which were correlated with percentage of task completed
strongly enough to be useful as covariates were typing speed (all subjects) and
contact hours with text editors (experienced subjects).

This paper describes a number of evaluation experiments designed to
establish the potential of Pitman's handwritten shorthand as an input for
computer transcription to text. Such a system would have applications in
verbatim reporting, the electronic office, and as an aid for the deaf. The
experiments described compare the performance of a proposed computer
transcription system for shorthand (described previously in this journal) with
the benchmark performance obtained using human transcription. In addition,
measurements on typical Pitman shorthand data are used to estimate potential
performance limits. It is concluded that the poor overall performance of the
proposed computer transcription system is due to a combination of three
factors: first, the simplified nature of the recognition algorithms used
compared with the knowledge-based techniques used by human shorthand readers;
secondly, ergonomic deficiencies of the data input devices used; and finally,
writer's lack of familiarity with the system and its capabilities. A proposed
strategy for improving the performance of the system by attention to the first
two of these deficiencies is given.

The Use of Q-Analysis and Q-Factor Weightings to Derive Clinical Psychiatric
Syndromes

The application of q-analysis to define clinical syndromes is described.
139 psychiatric inpatients were rated on a 65-item symptom checklist on a 0-3
scale. The patients and their symptom ratings formed a matrix which was sliced
at greater than one, transforming it to a binary matrix composed of the most
significant and persistent symptoms. Standard q-analysis was applied to this
matrix which demonstrated the predominance of q-connected depressive symptoms.
The method of applying a weighted relation on the shared face matrix, based
on the mean connectivity of each simplex, is described. The various
subcomponents, derived by different q-factor weightings could be seen to
represent different clinical syndromes. The emergence of these subcomponents
was not fully apparent from the standard q-analytic output. The use of
q-factor weightings to explore further the pattern of q-connectivity within a
simplicial complex is discussed.

IJMMS 1986 Volume 24 Issue 5

The concept of "rough" sets is used to approximate the analysis of an
information system describing 77 patients with duodenal ulcer treated by highly
selective vagotomy (HSV). The patients are described by 11 attributes. The
attributes concern sex, age, duration of disease, complication of duodenal
ulcer and various factors of gastric secretion. Two values of sex and age are
distinguished, five values of complications and three or four values of
secretion attributes, according to norms proposed in this paper. For each
patient, the result of treatment by HSV is expressed in the Visick grading
which corresponds to four classes. Using the method of rough classification it
is shown that the given norms ensure a good classification of patients.
Afterwards, some minimum sets of attributes significant for high-quality
classification are obtained. Upon analysis of values taken by attributes
belonging to these sets a "model" of patients in each class is constructed.
This model gives indications for treatment by HSV.

In general, behavioral data on the EDP user are not sufficient for planning
and organizing highly efficient man-computer interaction. It is therefore
proposed to extend the customary user concept and quantify the influence of the
user. Proceeding from the interpretation of the user as a "user system", a
method for valuation of user systems is presented and discussed, which rests on
the detection of indicators of a user system and their valuation on the basis
of an achieved level of "complicatedness" from the point of view of the
designer or operator of computers or EDP systems. The adequacy of the method
has been tested by a practical investigation of program developments in a
biomedical research center. The investigation was based on user and expert
inquiries.

Discrimination of Words in a Large Vocabulary Using Phonetic Descriptions

This paper analyses the results of several experiments performed with the
aim of selecting a suitable representation of words for an effective lexical
access.
A large vocabulary comprising the most frequent Italian words has been taken
into account.
Lexical access is performed in a bottom-up phase on the basis of broad
phonetic information, in order to reduce the number of vocabulary words that
must be verified. In a successive top-down phase, the constraints imposed by
the phonemic structure of this set of words select and schedule the
(context-dependent) sensory procedures which are most appropriate for
performing detailed phoneme verification analyses, in delimited signal
intervals, in order to determine, among the candidates, the word actually
spoken.
Access to the lexicon was performed using several different classes of
phonetic descriptions of words, ranging from a very rough one to others quite
close to the phonemic form, in order to substantiate the relationships between
the inaccuracy of the phonetic description and the confusability of the words
in the lexicon. Experiments have been performed both to access isolated words
and simulate a model for lexical access in continuous speech. The phonetic
descriptions of words have been obtained from the orthographic form by means of
a set of translation rules, taking into account also the possible degradations
that can occur in a real system. The results show that, by using a phonetic
description which can reasonably be obtained by means of feasible acoustic
processors, the number of words to be verified can be reduced, on average, to
about 17 for isolated words and to 260 for continuous speech.

Given the current widespread interest in expert systems, it is important to
examine the relative advantages and disadvantages of the various methods used
to build them. In this paper we compare three important approaches to building
decision aids implemented as expert systems: Bayesian classification,
rule-based deduction, and frame-based abduction. Our critical analysis is
based on a survey of previous studies comparing different methods used to build
expert systems as well as our own collective experience over the last five
years. The relative strengths and weaknesses of the different approaches are
analysed, and situations in which each method is easy or difficult to use are
identified.

IJMMS 1986 Volume 24 Issue 6

A unified abstract model of the human-computer interface is presented.
Examples from the existing literature that support various aspects of the model
are offered. Some other models of the human-computer interface are discussed.
The model is used to examine an existing workstation interface. The outcome of
the examination is a structured series of questions that could form the basis
for a future interface requirement. The potential productivity, application,
and development of the model are identified.

This paper is concerned with the use of icons in human-computer interaction
(HCI). Icons are pictographic representations of data or processes within a
computer system, which have been used to replace commands and menus as the
means by which the computer supports a dialogue with the end-user. They have
been applied principally to graphics-based interfaces to operating systems,
networks and document-processing software.
The paper attempts to provide a more systematic treatment of icon interfaces
than has hitherto been made, and to create a classification which it is hoped
will be of use to the dialogue designer. The characteristics, advantages and
disadvantages of icon-based dialogues are described. Metaphors, design
alternatives, display structures and implementation factors are discussed, and
there is a summary of some icon design guidelines drawn from a variety of
sources. Some mention is also made of attempts by researchers to measure the
effectiveness of icon designs empirically.

In this paper we analyse a subsystem, MINICON, of the UNICON interface to
the UNIX operating system using two well-known formal methods, Reisner's Formal
Grammar and Moran's Command Language Grammar. The contribution each technique
is able to make towards a complete specification of interface systems is then
identified and discussed.

Various methods of representing uncertainty are discussed including some
fuzzy methods. Representation and calculation of fuzzy expressions are
discussed and a symbolic representation of fuzzy quantities coupled with
axiomatic evaluation is proposed. This is incorporated into the PROLOG
language to produce a fuzzy version. Apart from enabling imprecise facts and
rules to be expressed, a natural method of controlling the search is
introduced, making the search tree admissible.
Formal expression of heuristic information in the same language, FUZZY
PROLOG, as the main problem language follows naturally and therefore allows the
same executor to evaluate in both "problem" space and "heuristic" space.
In addition, the use of variable functors in the specification of
bidirectional logic is discussed. The paper shows two areas of application of
higher order fuzzy predicates. As an introduction Warren's examples are
outlined and used with variable functors to illustrate their use in describing
some relatively conventional applications.
Translation of English into horn clause format is described and is used to
illustrate the simplicity of representation using variable functors.
Alternative formulations are also explored, typically the use of the
"meta-variable" in MICRO-PROLOG and using the "univ" operator.
Representation of rule generation and inference is addressed. Examples are
given where the expression of meta-rules in standard PROLOG are compared with
the expression of the same rules using "variable" predicate symbols. Some
meta-rules illustrated are clearly not universally valid and this leads to the
addition of fuzzy tokens.

Rule-based systems that ask the user and that also allow a not operator to
be used in the rules have existed for some time; see, for example, the work of
Duda, Gasching, Hart, Konolige, Reboh, Barrett & Slocum (1978). This paper
briefly explores an idea of Edmonds (1984) for bringing together such recent
developments within logic programming in order to provide a logic-based system
with an integral, automatic, strategy for asking. The discussion shows that a
simple and natural interpretation of PROLOG can provide a step towards
logic-based human-computer co-operation.

Support for Tentative Design: Incorporating the Screen Image, as a Graphical
Object, into PROLOG

The design process is a prime exemplar of a creative task in which humans
often change their minds. The design process considered is that of creating
pictures. It is argued that in order to accommodate tentative design of
pictures it is necessary to develop tools that maintain and have access to a
complete description of the picture being created. Extensions to PROLOG are
proposed that would serve as a basis for the development of such a tool. The
functioning of these extensions, which include human-computer interaction
rules, is shown to relate to the functioning of the design process.

An approach to the problem of automatic speech recognition based on
spectrogram reading is described. Firstly, the process of spectrogram reading
by humans is discussed, and experimental findings presented which confirm that
it is possible to learn to carry out such a process with some success.
Secondly, a knowledge-engineering approach to the automation of the linguistic
transcription of spectrograms is described and some results are presented. It
is concluded that the approach described here offers the promise of progress
towards the automatic recognition of multi-speaker continuous speech.

This paper is concerned with the testing of grammatical rules by computer.
The rules concerned are those which govern the order of nuclear elements in the
English clause, formulated in accordance with the principles of functional
grammar. The first part of the paper deals with the form and content of these
rules. Next, a procedure is described for the testing of these rules by means
of a program written in PROLOG. Finally, it is shown how the use of the
testing procedure leads to improvements in the formulation of the rules.

Many applications involve the construction of 3-D object models from which
images, often requiring a high degree of realism, are later produced.
Constructing such models frequently involves considerable human intervention,
even in cases where a physical model or the actual object to be modelled
exists. This paper describes an approach to the automatic construction of 3-D
object models using images of scenes. This method employs a representation of
the visible surfaces in a scene called the 2.5-D sketch and a model
construction process is described that utilizes multiple simulated 2.5-D
sketches.

A Three-Dimensional Interactive Graphics Workstation has been constructed
within the Human-Computer Interface Research Unit. The principal
accomplishment of this workstation has been to provide a tool enabling a user
to interact with a computer-generated image perceived in three dimensions.
This image is perceived by workstation users to exist in free space forward of
a VDU screen. A pilot experiment has been conducted where subjects interact
both with a simple model of a cube and a three-dimensional computer-generated
representation of the cube. The results indicate a significant positive
correlation between performances using the cube model and the 3-D
representation.

A Multi-Purpose System for Alpha-Numeric Input to Computers via a Reduced
Keyboard

A software package (CIPHERWRITER) is described which functions in a variety
of ways to permit alpha-numeric input using a substantially restricted subset
of the keys available on a conventional keyboard. It is presented in the joint
contexts, of background research which suggests that such a device could
conceivably benefit computer-naive personnel, and consideration of certain
specific requirements of the physically disabled.